I'm playing on a non-modded 1.6.2 client. If I try to make or play a single player world, Minecraft closes. I hit "Create New World" or "Play Selected World" and then it closes. Any help is appreciated. Also the PC I'm using is pretty low-end.

---- Minecraft Crash Report ----
// Why is it breaking :(

Time: 7/14/13 6:04 PM
Description: Rendering screen

java.lang.RuntimeException: Failed to check session lock, aborting
	at aln.h(SourceFile:44)
	at aln.<init>(SourceFile:30)
	at alj.<init>(SourceFile:16)
	at alk.a(SourceFile:83)
	at ats.a(SourceFile:1417)
	at awe.e(SourceFile:157)
	at awf.a(SourceFile:210)
	at awd.a(SourceFile:173)
	at awe.a(SourceFile:183)
	at bfb.b(SourceFile:718)
	at ats.S(SourceFile:686)
	at ats.d(SourceFile:619)
	at net.minecraft.client.main.Main.main(SourceFile:101)


A detailed walkthrough of the error, its code path and all known details is as follows:
---------------------------------------------------------------------------------------

-- Head --
Stacktrace:
	at aln.h(SourceFile:44)
	at aln.<init>(SourceFile:30)
	at alj.<init>(SourceFile:16)
	at alk.a(SourceFile:83)
	at ats.a(SourceFile:1417)
	at awe.e(SourceFile:157)
	at awf.a(SourceFile:210)
	at awd.a(SourceFile:173)
	at awe.a(SourceFile:183)

-- Screen render details --
Details:
	Screen name: blq
	Mouse location: Scaled: (146, 103). Absolute: (292, 272)
	Screen size: Scaled: (427, 240). Absolute: (854, 480). Scale factor of 2
Stacktrace:
	at bfb.b(SourceFile:718)
	at ats.S(SourceFile:686)
	at ats.d(SourceFile:619)
	at net.minecraft.client.main.Main.main(SourceFile:101)

-- System Details --
Details:
	Minecraft Version: 1.6.2
	Operating System: Windows XP (x86) version 5.1
	Java Version: 1.7.0_25, Oracle Corporation
	Java VM Version: Java HotSpot(TM) Client VM (mixed mode), Oracle Corporation
	Memory: 41696096 bytes (39 MB) / 71376896 bytes (68 MB) up to 1037959168 bytes (989 MB)
	JVM Flags: 1 total; -Xmx1G
	AABB Pool Size: 0 (0 bytes; 0 MB) allocated, 0 (0 bytes; 0 MB) used
	Suspicious classes: No suspicious classes found.
	IntCache: cache: 0, tcache: 0, allocated: 0, tallocated: 0
	Launched Version: 1.6.2
	LWJGL: 2.9.0
	OpenGL: Intel 945GM GL version 1.4.0 - Build 7.14.10.4926, Intel
	Is Modded: Probably not. Jar signature remains and client brand is untouched.
	Type: Client (map_client.txt)
	Resource Pack: Default
	Current Language: English (US)
	Profiler Position: N/A (disabled)
	Vec3 Pool Size: ~~ERROR~~ NullPointerException: null

Duplicate of MC-10167, please use the search function to see if your bug has already been submitted. Currently over 58% of tickets are being closed as duplicate.

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Minecraft Bedrock Edition is Not creating the worlds and I don't have one! It is new and a bug?

How!!!!

Please fix this

With All my respect,  Thanks if you will fix it